Resilient bug-sized robots keep flying even after wing damage

Bumblebees are clumsy fliers. It is estimated that a foraging bee bumps into a flower about once per second, which damages its wings over time. Yet despite having many tiny rips or holes in their wings, bumblebees can still ...


Combining 3D printing and sensors for safer, cheaper flying

The aeronautical industry has transitioned to the use of advanced composite materials because of their lightweight properties, strength and durability. Together with increased aircraft productivity and performance, using ...

Energy & Green Tech

New energy harvesters show potential that fits like a glove

A group of University of Texas at Dallas researchers and their colleagues have made significant improvements to energy-harvesting yarns they invented called twistrons, which are made from carbon nanotubes and produce electricity ...

Electronics & Semiconductors

Lithium-ion batteries that last longer in extreme cold

When temperatures fall below freezing, cellphones need to be recharged frequently, and electric cars have shorter driving ranges. This is because their lithium-ion batteries' anodes get sluggish, holding less charge and draining ...

Energy & Green Tech

New method to convert plastic trash into clean hydrogen fuel

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a new method for plastic waste to be converted into hydrogen based on pyrolysis, a high temperature chemical process.

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Carbon nanotube

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 28,000,000:1, which is significantly larger than any other material. These cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science, as well as potential uses in architectural fields. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Their final usage, however, may be limited by their potential toxicity.

Nanotubes are members of the fullerene structural family, which also includes the spherical buckyballs. The ends of a nanotube might be capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 1/50,000th of the width of a human hair), while they can be up to several millimeters in length (as of 2008). Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs).

The nature of the bonding of a nanotube is described by applied quantum chemistry, specifically, orbital hybridization. The chemical bonding of nanotubes is composed entirely of sp2 bonds, similar to those of graphite. This bonding structure, which is stronger than the sp3 bonds found in diamonds, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces. Under high pressure, nanotubes can merge together, trading some sp² bonds for sp³ bonds, giving the possibility of producing strong, unlimited-length wires through high-pressure nanotube linking.

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